Traffic control devices, such as stop signs and traffic lights, are used to regulate, warn, or guide vehicular traffic. However, problems arise when vehicle operators fail to abide by traffic control devices, whether intentionally or unintentionally. As one example, when vehicle operators fail to stop at stop signs, or accelerate when a traffic light is red or about to turn red, accidents and fatalities may result, as well as costs associated with repairing damages and hospital bills for injured parties. As another example, vehicle operators may accelerate as they approach an intersection and then slam on the brakes when they notice a stop sign, or slam on the brakes when a traffic light changes from green to yellow to red before they have reached the intersection. Abruptly braking in this way may waste fuel and cause unnecessary wear and tear of vehicle components. Accordingly, vehicle operators' failure to abide by traffic control devices may lead to safety hazards as well as inefficient fuel usage.
Various approaches for reducing the safety hazards and fuel inefficiencies associated with traffic control devices are known. In one approach, US 2010/0070128 describes providing motorists with information regarding intersections on their travel route, thus enabling them to operate their vehicles in a manner that increases fuel economy and/or road safety. For example, a computing device receives traffic-related data from a plurality of sensors at traffic signaling locations, analyzes the data, and wirelessly transmits relevant data to on-vehicle technology which may automatically adjust vehicle operating parameters or alert the driver to adjust operating parameters manually. This traffic-related data may include the signaling status of a traffic light, e.g., an indication of when the traffic light will turn green. However, in this approach, the traffic-related data does not include data on static traffic control devices such as stop signs.
The inventors herein have recognized that it may be advantageous to develop different vehicle control strategies corresponding to different traffic control devices. That is, the inventors herein have recognized that a type of traffic control device (e.g., stop sign or traffic light) may be determined as a vehicle approaches an intersection, and a control strategy tailored to promoting fuel efficiency and safety for known vehicle behavior in approaching that type of traffic control device (e.g., obligatory stopping at a stop sign and conditional stopping at a traffic light depending on its state) may be adopted.
In one example approach, a method for operating a vehicle comprises adjusting operation of the vehicle in response to whether a detected traffic control device is a stop sign is or a traffic light. For example, if the detected traffic control device is a stop sign, the method may further include evaluating a current vehicle state, the current vehicle state based on a distance between the vehicle and an intersection associated with the stop sign, a distance between the vehicle and a next forward vehicle, a speed of the vehicle, and a deceleration rate of the vehicle, and determining a vehicle control strategy based on the current vehicle state.
Alternatively, if the detected traffic control device is a traffic light, the method may further include evaluating a current vehicle state, the current vehicle state based on a distance between the vehicle and an intersection associated with the traffic light, a distance between the vehicle and a next forward vehicle, a speed of the vehicle, and a deceleration rate of the vehicle, determining a current traffic light state, predicting a timing of a traffic light state change, and determining a vehicle control strategy based on the current vehicle state, the current traffic light state, and the predicted timing of the traffic light state change.
The inventors herein have further noted that it in hybrid vehicles, it may be advantageous for the vehicle control strategy to include adjusting operation of a disconnect clutch based on the type of traffic control device detected at an oncoming intersection. For example, one approach may include detecting a traffic control device at an intersection the vehicle is approaching, and releasing and applying a disconnect clutch arranged in a driveline of the vehicle intermediate an engine and a starter/generator based on the type of traffic control device detected.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.